In addition to the Summer LEGO Star Wars sets, Amazon also now got the entire line of Monster Fighters sets instock! As always, free shipping on orders above $25 and no tax to most states. Thanks to Jonathan for the tip.
In terms of the price per piece ratio, Monster Fighters is considered to be a very good value compared to Star Wars. Coupled with great sets, this could probably explain why most of the sets are already out of stock at LEGO Shop at Home!